Centrifugally armed fuse



March 6, 1956 J. A. PEcK 2,737,113

CENTRIFUGALLY ARMED FUSE Filed Feb. 7, 1952 Fig. 2. F/g. 3.

IN VEN TOR.

UIHILIEIIIIU TORNEY Josep/04H56, 9565/2550,

United States Patent O 2,737,118 CENTRIFUGALLY ARMED FUSE Joseph A. Peck, deceased, late of Worcester, Mass., by Allen S. Peck, executor, Worcester, Mass., assignor to the United States of America as represented by the Secretary of the Army Application February 7, 1952, Serial No. 270,374 1 Claim. (Cl. 102-79) This invention relates to a bomb fuse which is automatieally armed by the centrifugal action of the spinning bomb as it falls free in space.

The arming of a bomb during its free fall is important in the interests of safety since bombs should not be loaded and carried when in an armed condition. Moreover, arming immediately prior to a drop is equally dangerous.

To obviate these diiiiculties, the present invention contemplates arming the bomb after dropping'and falling several hundred feet. The fuse, which is the subject matter of this invention, is a centrifugally actuated mechanism and must accordingly be applied to a bomb having tail surfaces that impart a rotation to the bomb.

In the drawing, Fig. 1 shows the fuse impositioned in a bomb. Fig. 2 shows the fuse in an unarmed condition.`

Fig. 3 shows the fuse in an armed condition with the inertia firing plunger on the way down toward the primer. Fig. 4 is a section of Fig. 2 at 4--4. Fig. 5 shows the fuse in an armed condition before the inertia tiring plunger has begun to descend.

In Fig. 1, 2 is the main body of a special type vaporizing bomb wherein the agent to be vaporized is contained in the main bomb body 2; the vaporizing fuel is contained in the nosepiece 3. 5 is a primer extending from the fuel container 3 to the fuse 10. 7 is a transverse bulkhead supporting the fuse 6 and the primer tube 4 containing the primer 5, 8 is the folding tail surfaces that stabilize the bomb and impart the rotational impulse.

In Fig. 2, 10 is the fuse base having internal and external threads at opposite ends, a bulkhead 13 across the middle and radial openings 11 in the bottom section. 12 is the fuse head having external threads on the lower portion and radial openings or bores 27 in the upper portion. These bores are fitted with pistons or arming pins 26, biasing springs 32 and nally closure caps 34. The fuse head also contains the firing plunger 20 having a tiring pin 19 at the bottom and a circumferential groove 28 near the top. Pistons 26 have a pin 22 which engage this groove when the pistons are biased at their inner positions by means of springs 32. When the parts are in this unarmed position, the ring plunger 20 cannot fall and the tiring pin cannot contact the primer. Firing plunger 20 has the top chamfered at an angle 24 to permit the plunger to be pushed up and locked in the unarmed position against the pressure of biasing springs 32.

Piston 26 has a depression 30 to receive the tapered coil spring 32 and closure cap 34 has a similar depression making it possible for the piston 26 to move out of its extreme position in contact with the closure cap. Coil spring 18 serves to bias the firing plunger in an upper position away from the primer 14. Below the primer is the booster tube 16 which in turn serves to ignite the primer 5.

The fuse is assembled by placing the booster tube 16 in position in the fuse base on the booster tube ring and placing the primer 14 held in the primer holder 17 above the booster. Primer holder 17 is made of a soft metal making it possible for the ring pin 19 to indent the holder and detonate the primer.

The fuse head 12 is next assembled by inserting the pistons 26 and springs 32 behind the closure cap 34, the latter having a tight press fit in the fuse head. Firing plunger 20 is next pushed up into the unarmed position and the assembled fuse head with biasing spring 18 is ICE screwed into position in the fuse base 10. This locks the primer 14 and booster 16 in position and the fuse is ready for assembly into the bomb.

When assembled in a bomb as shown in Fig. l, the longitudinal axis of the bomb and fuse coincide with the result that a rotation of the bomb causes the fuse to rotate about its longitudinal axis. When the bomb is dropped, the tail surfaces impart a rotational velocity to the bomb and fuse which cause the piston weights to recede from groove 22 in the firing plunger 20 thus permitting the latter to move downwards as shown in Fig. 3. During the free fall of the bomb the firing plunger will not move downward even after arming due to the biasing action of spring 18. Upon impact however, the inertia of the ring plunger is sufficient to overcome the biasing action of spring 18. The plunger then falls and firing pin contacts primer holder 17 and detonates the primer 14 which in turn ignites the booster and the bomb.

After the bomb is detonated, the primer tube 4 serves as a chimney for the hot gases from the burning fuel in container 3. These gases also pass through the fuse base and out through the radial openings 11. Thus the mechanism serves `the dual function of detonating the bomb as well as venting the burning gases. The latter function is important and becomes essential due to the central disposition of the fuse.

The piston weights 25 are of such mass and the biasing springs 32 are of such tension that the centrifugal force of the falling bomb will not force the piston weights out until the bomb has fallen quite free of the airplane. In practice, the arming R. P. M. of the fuse has been varied from 1750 to 3200. A iinal R. P. M. of 2200 was used as an average operating speed. The resulting fuse will arm in a fall of approximately 300 feet, which is satisfactory.

The advantages of this fuse are its increased sensitivity after arming, complete sealing of the fuse mechanism from moisture, elimination of external safety pins, ease of assembly into the bomb, absolutesafety during handling and elimination of air bursts.

What is claimed is:

In a vaporizing bomb comprising a cylindrical body section and a nose section, a perforated horizontal dividing wall between said body and nose sections, a central chimney extending from said perforation to the nose section of the bomb, said nose section containing vaporizing fuel which burns to heat the body section of the bomb, the products of combustion of said vaporizing fuel passing up through the central chimney, said central chimney containing a powder train extending down to the vaporizing fuel, a centrifugal action fuse positioned above said chimney, said fuse comprising a fuse base and a fuse head, said fuse base comprising a vertical Vtubular section having a perforated horizontal dividing wall and radial wall, perforations in the vertical tubular section below said horizontal dividing wall, said fuse head comprising a vertically moving firing plunger held in xed position by spring biased latching means, said means being made to unlatch the tiring plunger by centrifugal action due to rotation of the fuse, a primer positioned under said firing plunger, a booster tube positioned under said primer and extending through the perforated horizontal dividing Wall into the vertical tubular section.

References Cited in the file of this patent UNITED STATES PATENTS 1,145,937 Stout et al July 13, 1915 1,770,447 Woodberry July 15, 1930 1,877,232 Duncan Sept. 13, 1932 1,878,491 Goss Sept. 20, 1932 2,119,697 Anderson June 7, 1938 2,472,821 Graumann June 14, 1949 2,598,157 Everett May 27, 1952 

